The present invention relates generally to a handle for a utility tool and, more specifically, to a handle for a tire bead breaking wedge.
Tire bead breaking wedges are known in the art and are in commercial use. Such tools generally comprise an elongate handle affixed at one end to a wedge head. The wedge head comprises an elongate body, typically formed from cast metal, having a striking surface at one end and a wedge edge at an opposite end. A circular in cross-section through- bore extends through the tool head at a location representing the center of mass.
The handle for the subject type of tool is generally of elongate, cylindrical configuration extending from a gripping end to an inverted frustro-conical forward end. The handle may be of wood, metal, plastic, or a composite composition. The forward end of the handle may further be coated with a rubber or other high coefficient of friction material.
Assembly of the wedge head to the handle is achieved by inserting the handle gripping end downward through the head bore until the forward end of the handle enters the bore of the head. The dimension of the forward end of the frustro-conical handle portion is oversized relative to the head bore. Accordingly, driving the frustro-conical handle portion downward into the bore of the head wedges the forward portion of the handle into the bore and establishes a tight, frictional connection between the handle and wedge head.
In use, the user positions the working edge of the tool between a wheel rim and tire bead. Thereafter, a hammer is applied to the striking surface, serving to drive the wedge edge downward until the bead of the tire is disengaged from the wheel rim. Should the bead prove resistant, a user of the bead-breaking wedge will typically pry the wedge head back and forth until engagement between the bead and the wheel rim is broken.
A bead breaking wedge of the aforementioned type is commercially sold as a Model 35329 wedge and T11E head by Ken-Tool Company, of 768 E. North Street, Akron, Ohio 44305. While the implement works well and has met with considerable commercial success, it has been found that rocking the wedge back and forth against the tire bead can, over time, cause the handle forward end portion to work its way loose from the wedge head, requiring a re-tightening by the user. Still further, repeated rocking action of the wedge head relative to the handle may act to frictionally wear away the portions of the inverted frustro-conical handle end lying along the wedge head longitudinal axis until only the lateral sides of the forward handle end remain in frictional engagement with the wedge head. In this condition, the wedge head may become free to rock backward and forward about the lateral sides of the forward handle end, xe2x80x9cplayxe2x80x9d that is undesirable to the intended purpose of the tool. Eventually, the head will become loose from the handle and a retightening will be required. However, once the handle forward portion becomes worn to a considerable degree, a re-tightening of the handle to the tool head in known tools becomes increasingly problematic.
In order to postpone, if not eliminate, loosening between the handle forward end and the wedge head, handle manufacturers have incorporated ribs along the inverted frustro-conical outer surface of the forward handle end. The ribs engage circular sidewalls defining the wedge head bore. As the tool is used, the ribs wear away at a slower pace and a positive frictional engagement between the head and the handle is prolonged. The ribs, however, are of narrow width dimension making the area of surface to surface contact between the handle end and the wedge head less than desired. In addition, though occurring at a slower pace, the ribs will eventually wear away. When the ribs are gone, the handle and wedge head will loosen in the manner described above. A repeated retightening of the wedge head connection with the handle will be increasingly required and over time, re-tightening, as explained above, becomes increasingly problematic.
A second deficiency in known handles for tire bead breaking wedges is that users commonly contact the wheel rim with a portion of the tool proximate the working end. Such contact can, in time, cause a structural failure of the handle at the point of impact. In addition, the handle gripping area in known tools is generally smooth and regular. Establishing and maintaining a tight grip with the tool handle can become increasingly difficult as the user becomes fatigued.
Accordingly, there is a need for a tire bead-breaking tool having a head to handle frictional connection that will not degrade from repeated use of the tool over time. Moreover, such a tool handle should provide the user with a positive gripping area and incorporate added strength to areas prone to damage from contact between the handle and a wheel rim.
It is, therefore, an object of the invention to provide a handle for a utility tool that establishes and maintains a positive frictional engagement with the tool head.
A further object is to provide a handle for a utility tool that provides a user with a comfortable gripping portion.
Yet a further object is to provide a handle for a utility tool that self-tightens the frictional connection between the handle and the tool head.
Another object of the invention is to provide a handle for a tire bead-breaking tool providing structural reinforcement to handle portions prone to contact with a wheel rim during use.
A further object of the invention is to provide a handle for a tire bead-breaking wedge that is comfortable to grip and wield and that provides a positive application of mechanical advantage through the tool head to the working wedge edge.
A further object is to provide a handle for a tire bead-breaking wedge that is economically and readily manufactured and readily connected to a tool head.
The aforementioned objectives, and others that will be apparent to one skilled in the art, are achieved by a tool handle described and claimed below. The handle comprises an elongate gripping portion stepping at a forward shoulder to a shield portion having a thicker dimension than the gripping portion. An inverted frustro-conical handle working portion is connected to a forward end of the shield portion and is configured oblong in cross-section having protruding opposite end surfaces and substantially less protruding lateral surfaces disposed between the end surfaces.
The working portion of the handle wedges within an oval-shaped through-bore of a tool head and establishes positive frictional engagement between the protruding surfaces and tool head bore sidewalls. The protruding surfaces align and face along the longitudinal plane of the wedge head and use of the tool serves to drive the protruding surfaces into the bore, whereby reinforcing the frictional connection between the handle and the tool head. Less protruding lateral sides of the handle working end are separated from the sides of the tool head bore by gaps and thereby avoid contact therewith.
The less protruding lateral sides of the handle working end are preferably flat and extend from the working end along the shield portion and thence along the handle gripping portions. The flat surfaces break the smooth curvature of the handle gripping portion circumference and provide longitudinal edges that enable the user to establish a positive grip upon the handle. The shield portion is disposed at a location along the handle to afford structural reinforcement where the handle is prone to contact a wheel rim in use.